Testing & Diagnostics

Hip Dysplasia Score

The numerical or graded result from hip joint screening (OFA grades, PennHIP distraction index, or BVA/KC score). Used to assess breeding suitability and individual joint health risk.

Hip dysplasia scoring quantifies hip joint conformation and laxity to guide breeding decisions and assess individual health risk. Three major scoring systems are used globally.

OFA Hip Grades (United States)

The OFA evaluates ventrodorsal hip radiographs in sedated dogs at 24+ months. Three radiologists grade independently; the modal grade is reported.

Passing grades (OFA certified): Excellent, Good, Fair Non-passing grades (OFA not certified): Borderline, Mild, Moderate, Severe

Breeding recommendations: only Excellent, Good, and Fair dogs should be bred from. Dogs from Excellent × Excellent matings are substantially less likely to produce dysplastic offspring than matings involving Fair or borderline dogs.

PennHIP Distraction Index (United States)

PennHIP measures passive hip laxity under sedation using a distraction device. The Distraction Index (DI) reports how far the femoral head moves from the acetabular center:

  • DI 0.0: no laxity (ideal)
  • DI >0.3: moderate laxity; increased OA risk
  • DI >0.7: high laxity; high OA risk

PennHIP reports DI relative to breed distribution — dogs in the tightest percentile for their breed are prioritized in breeding programs.

BVA/KC Score (United Kingdom)

The British Veterinary Association/Kennel Club system scores nine radiographic features from 0–6 each, for a total score of 0–106 (both hips combined). Lower scores indicate better hip conformation.

  • Score 0–4: excellent
  • Score 5–25: generally acceptable for breeding; breed median should be consulted
  • Score >breed median: not recommended for breeding

Using Scores in Practice

No scoring system guarantees hip-healthy offspring — dysplasia is polygenic (many genes involved) and environmentally influenced. However, consistently selecting breeding pairs from the best scores available within a breed progressively reduces the population frequency of severe dysplasia over generations. OFA statistics show measurable improvement in hip scores across multiple breeds over 40 years of screening programs.